Question

multiple select question
select all that apply
group 18 elements
all have eight electrons in their outer energy level
have complete outer energy levels
include helium, neon, and argon, among others
combine easily with other elements to form compounds
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Explanation:

Group 18 elements (noble gases) have complete outer energy levels. Helium has 2 electrons in its outer level (due to its small size, the first energy level can hold only 2 electrons), while neon, argon, etc., have 8 electrons in their outer level. They are inert and do not combine easily with other elements. Helium, neon, argon are examples of Group 18 elements.

Answer:

• "have complete outer energy levels"
• "include helium, neon, and argon, among others"